How does one update our mailing address in HDFC?
Too many unanswered questions within your question. The biggest being if your address is not currently permanent, how do you travel without an AADHAR throughout India, or between Countries without a Passport? Not voting answers why you might not have a Voter ID. But the other forms of ID they request seem like reasonable ones. Addresses can be faked rather easily, so eliminating a bill saying where you reside as proof of residency is one more step to eliminating fraud.